To make the fried onions, heat about 2-3 inches of canola oil in a heavy bottomed pan over medium-hight heat until it reaches 350 degrees. Combine the flour, water, egg, and baking powder in a shallow pan or bowl. Working in small batches, dip the onion slices in the batter. Make sure you shake the onion a little over the bowl to get rid of excess batter. Add battered onions to the oil and fry until crisp and golden brown, approximately 2-3 minutes. Remove to a paper towel lined baking sheet. Once all onions are fried, keep them warm in an oven set on low.

Spread the olive oil on the cut sides of each bun. Add the buns cut side down and the hot dogs to a hot grill or grill pan over medium-high heat. Cook until buns are toasted and hot dogs are warmed through, approximately 4-5 minutes. Remove from grill.

Place hot dogs in the hot dog buns. Top each with your favorite barbecue sauce, blue cheese crumbles, and a large handful of fried onions. Serve immediately.